Long-term Follow-up After Endometrial Ablation in Finland: Cancer Risks and Later Hysterectomies

To study the risk of endometrial cancer and breast cancer and the hysterectomy rate after endometrial ablation.

In this retrospective cohort study, records of all women with endometrial ablation at ages 30-49 years in Finland (1997-2014) were extracted from the Hospital Discharge Register and linked to the Cancer Registry and Finnish Central Population Register. The primary outcome was cancer incidences in the endometrial ablation cohort compared with those in the background population of the same age. Secondarily, the postablation hysterectomy rate was compared with that of a control cohort of similar-aged women extracted from the Finnish Central Population Register. Multivariate regression models with adjustment for age, parity, number of cesarean deliveries, history of sterilization, and the duration of follow-up were evaluated as risk factors for postablation hysterectomy.

In total, 154 cancers (standardized incidence ratio [observed-to-expected ratio] 0.96, 95% CI 0.82-1.13) were diagnosed among 5,484 women treated with endometrial ablation during the follow-up of 39,892 women-years. The standardized incidence ratio for endometrial cancer was 0.56 (95% CI 0.12-1.64) and for breast cancer 0.86 (95% CI 0.67-1.09). A total of 1,086 (19.8%) women had postablation hysterectomy. Risk of hysterectomy was almost fourfold in the endometrial ablation cohort compared with 26,938 women in a control group (adjusted hazard ratio [HR] 3.63, 95% CI 3.32-3.96). Factors predisposing to postablation hysterectomy were leiomyomas (adjusted HR 1.78, 95% CI 1.03-3.10), age younger than 35 years (adjusted HR 1.44, 95% CI 1.15-1.81), at least two prior cesarean deliveries (adjusted HR 1.27, 95% CI 1.04-1.55), and history of sterilization (adjusted HR 1.15, 95% CI 1.01-1.32).

Endometrial ablation was not associated with an elevated endometrial cancer or breast cancer risk in Finland. Leiomyomas, young age, and history of prior cesarean deliveries or sterilization were associated with an increased risk of postablation hysterectomy.